For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition 65 WarningRemoval Procedure
Warning: Refer to Approved Equipment for Collision Repair Warning in the
Preface section.
Warning: Refer to Collision Sectioning Warning in the Preface section.
Warning: Refer to Glass and Sheet Metal Handling Warning in the Preface section.
Disable the SIR System. Refer to SIR Disabling ...
Center Pillar Upper Garnish Molding Replacement
Preliminary Procedure
Remove the center pillar lower garnish molding. Refer to Center Pillar
Lower Ga rnish Molding Replacement
Remove the seat belt from the front seat. Refer to Driver or Passenger
Seat Retractor Side Belt Replacement
Center Pillar Upper Garnish Mo ...
Installation Procedure
Create 5 x 18 mm (4/16 x 11/16 in) slots for MIG-Brazing along the edges
of the front wheelhouse front panel as noted from the
original panel.
Create a 5 x 18 mm (4/16 x 11/16 in) slot for MIG-Brazing where front
wheelhouse front panel and front wheelhouse overlap.
C ...